Ab initio calculations of the structural and elastic properties of CoSi₂

Under GGA, the geometry, energy, electronic structure, and elastic properties of the CoSi2 have been investigated by using ab initio plane-wave ultrasoft pseudopotential method. The calculated equilibrium lattice parameter a and elastic stiffness constants c(11), c(12), and c(44) are in better agreement with the experimental values than those obtained by both the VAMP and FLAPW with LDA. For engineering and technological applications, the isotropic elastic properties, including the shear modulus G, the bulk modulus B, Young's modulus E, and Poisson's ratio nu, are also calculated for polycrystalline CoSi2 with Voigt, Reuss, and Hill approximations. The lower Poisson's ratio nu of 0.327 means an increase in the volume is associated with the uniaxial tensile deformation and the higher ratio of bulk modulus to shear modulus B/G of 2.56 indicates the ductility of CoSi2 which is in accordance with the metallic property of CoSi2 obtained by the density of states.